1. Field of the Invention
The present invention relates generally to supports for motors, and more particularly to an improved method of manufacturing and composition of movable supports required for motors.
2. Description of the Related Art
Motor supports of which the exemplary embodiments herein are of a general type are well known in the art and, having regard particularly to supports for motors or articles of machinery, prior art examples will be given in the following.
It is vital to understand that the present invention has particular significance and importance in the environment of supporting motors for driving machinery through belts and pulleys and for supporting the machinery that is driven through belts and pulleys by motors.
In an exemplary but not restrictive environment, a motor is equipped with a drive pulley of a fixed diameter and an adjoining powered piece of machinery is equipped with a driven pulley of a fixed diameter. Thus, an increase in the work load will result in a decrease in the speed of the driven pulley and increase the tension on the belt which transfers power from the motor to the driven equipment. To maintain tension equilibrium between the belt and the spring, the center distance between the motor and the driven equipment reduces. This reduction minimizes belt slippage and allows the driven equipment to efficiently receive power and accelerates returning to normal operating speed with the result of reduced wear on the pulleys, belts, and bearings while reducing energy consumption. As the driven belt returns to normal operating speed, the center distance between the motor and the driven equipment also returns to substantially normal spacing.
In order to effect such changes, a motor is mounted on a movable carriage supported on a fixed base which has two or more parallel and cylindrical solid rods that define parallel rails. The carriage is able to slide on the rails so that the carriage can move rapidly to achieve changes in speed. If the carriage is to be moved manually on the rails, as is usually the case, it can be appreciated that it is essential that such movement be accomplished with a minimum amount of physical exertion.
Various expedients have been employed in attempts to properly support the carriage so that the carriage and the motor load thereon are evenly transferred to the rails and yet to support the carriage in a way to reduce friction resistance to the sliding of the carriage on the rails.
In an early motor support, exemplified in U.S. Pat. No. 2,762,663 to Sloyan, a fixed portion of the motor support has parallel rails which are made fast to transverse end cleats and the motor carriage has channel-shaped gliders that encompass portions of the rails and provide a race between the corners thereof and the curved surfaces of the rail with a series of balls being disposed within such defined races. It has been found that the ball bearings, which establish line contacts, are not efficient for many reasons including the fact that grooves are developed in the rails which cause the sliding action to lose efficiency and which also cause the carriage to have a tendency to chatter.
In related U.S. Pat. No. 2,833,597 also to Sloyan, the gliders are composed of rectangular tubes which are square in cross section and have an inside dimension materially greater than the outside dimension of the cylindrical rails. C-shaped bearing assemblies are provided between the gliders and the rails. Such assembly consists of a metallic bushing which has a freely slidable, non-chattering fit on the rails, a C-shaped metallic member, equal in length to the bushing, the external circumference of which makes line contact with three adjacent internal surfaces of the square tube glider, a member of resilient material equal in length to and having a push fit over the bushing and having an external diameter slightly greater than the nominal internal diameter of the C-shaped member, so that as the assembly of bushing, resilient member and C-shaped member are forced into the glider, that portion of the resilient member not enveloped by the C-shaped member but which contacts the internal surface of the remaining wall of the glider becomes slightly distorted due to being somewhat compressed between the bushing and the glider. The result is that the bushing becomes slightly non-concentric with the glider. However, the advantage of the resiliency overshadows the lack of concentricity. The resiliency does much to reduce noise likely to develop between the two metallic parts, the bushing and the rail. A typical example is that any noise developed at the source of an air conditioning system is likely to be telegraphed to every room in a building.
U.S. Pat. No. 4,252,380 to Sloyan has been an industry standard for slidable motor supports since the early 1980s, and is a motor support having a carriage movably mounted by means of gliders, which are cross-sectionally square elongated tubes, that slidably encompass parallel elongated fixed rails on a stationary base bed with plastic or metal bearing sleeves press fitted in the end portions of the glider tubes to bearingly support them on the rails and transfer the motor load on the glider tubes to the rails in a friction free manner with a reservoir of a viscous lubricant within the center portions of the glider tubes. This motor support was a culmination of decades of work, and served the industry. However, such motor support may be difficult and time-consuming to manufacture. In an era of financial concerns, a more cost-effective and high quality motor support is needed
Thus, what is needed is a slidable motor support that is highly effective, yet more easily manufactured and less expensive.